A Study on Creep Behavior of Wood Flour- Recycled Polypropylene Composite

The creep behavior of wood flour- recycled polypropylene composites (with and without compatibilizer) has been evaluated in this study. For this purpose، virgin polypropylene (PP) was thermo-mechanically degraded by five times of extrusion under controlled conditions in a twin-screw extruder at a rotor speed of 100 rpm and at temperature of 1900C. The virgin and recycled polypropylene were mixed with the wood flour (50/50% W/W) as well as the compatibilizer (0، 2% W/W) by a counter-rotating twin-screw extruder to manufacture the wood flour-PP composites (WPCs) samples. The nominal cross section of the manufactured composites was 70×10 mm2. Short term flexural creep test at 30% of ultimate bending load was performed by using flexural creep equipment. The total time to complete every test was 120 min (60 min creep and 60 min recovery). Results revealed that recycling of the PP reduced the creep resistance in composites containing recycled polypropylene. Also results have shown that with the presence of compatibilizer (MAPP) creep deflection، creep factor and relative creep decrease and creep modulus increase. The composites containing virgin PP and MAPP exhibited higher creep resistance than those containing recycled PP.